Acid

Postby Chippy_Tea » Mon May 05, 2014 14:06

Winemaking Acid

Acid is one of those wonderful areas of home-brew wine making that permits large amounts of mucking about. Your only contribution to the topic of acid may be to simply waft a bottle of Jif lemon at each demijohn. However, if you are prepared to expend the time and effort, whole afternoons can be frittered away in the kitchen mixing together at least four different types of acid and performing laboratory tests to convince yourself that you are not wasting time.

If you are new to the esoteric world of home-brew wine making you may be puzzled as to what this acid business is all about. Acid is one of the attributes of wine that conspires with many other factors to produce the all encompassing concept of quality. We are all familiar with the concept of acidity. A drop of lemon juice on the tongue will remind you. Those of you with some knowledge of chemistry will be familiar with the phrases acid and alkali. Acid equals lemon juice, alkali means bicarbonate of soda. Mix the two together and the resultant cocktail will fizz in a satisfying manner. Wine, be it home made home brew home brew or 'real' will be acidic. This is good. It adds to the flavour. A perfect wine will be well balanced. An under acid (alkali) wine will taste bland, and a wine which is overly acid will taste sharp, like orange juice. The art of attaining the correct acidity is all part of the fun of home brew wine making.

There exists a number of scales by which we measure acidity. The one used by most winemakers is somewhat literary. The scale consists of three stages.

Gosh that's sharp.
Thats about right.
How uninteresting.

These statements describe the finished wine. There is no inclination to make adjustments, all that is generated is a mental note to mix things up in a different order next time.

The winemaker who has time on his hands will broadcast this fact by taking things a stage further. The universal win making measure of acidity is parts per thousand sulphuric acid (ppt). Sulphuric acid never gets near wine, and is thus logically (?) chosen as the scale. Wine ranges from 3.0 ppt for a dry light wine, to 4.5ppt for a sweet full bodied wine. The afore mentioned winemaker will go to considerable pains to measure the acidity until it lies within 0.1ppt of where he wants it. The judicious adding of acid and calcium carbonate will be employed to achieve this end.

You may also remember from your school days the use of pH to measure acidity. pH counts the number of bits of acid in the wine and can be measured by indicator paper, but this does not work very well. Either you guess, or you do things properly.

You may feel justified in thinking this is all a bit unnecessary. It is. Very much so. When you start home brew wine making it is only necessary to add a couple of teaspoons of acid and forget about it. Only the more adventurous go on to buy the toys required to measure and adjust acidity.

So far in this lesson I have lightly tossed about the phrase 'add acid'. How does one achieve this? The ingredients that we make home made home brew home brew wine from do not, as a rule, contain enough acid to produce a well balanced bottle of wine. We must add some. 'Some' means squeeze the juice of a couple of lemons into the must. Alternatively buy a tub of citric acid and chuck some of that in. This will allow you to make fairly consistent wines.

But, (why is there always a 'but'?) the story does not end here. The winemaker can get hold of malic, lactic, citric, tartaric and succinct acids. This is before you consider the mysteries of tannic acid, but that topic alone will fill a page.

Essentially, each acid imparts different qualities. Many winemakers use a mix of citric, malic and tartaric, but most of us just rely solely on citric. One can also obtain precipitated chalk, this is calcium carbonate, and is added to the wine to reduce the acidity.

Citric Acid. The is the most popular acid, it has a characteristic fruity taste. It is found in things like lemons and oranges, which is why these fruits are often included in older recipes. Citric acid also imparts brilliance to wine.

Malic Acid. Found in things like apples. This acid is said to help speed fermentation. There also exists stuff called malolactic bacteria, this can be persuaded to start a small fermentation in bottled wine, where the malic acid is converted to less acid lactic acid in a process called malolactic fermentation. This is generally considered a good thing.

Tartaric Acid. The predominate acid in grapes. Imparts a vinous character to the wine, but is apt to crystallise out of the wine some time after bottling because it is rather unstable in solution. This can lead to a deposit in the bottom of a bottle of previously clear wine. This in turn gives an excellent excuse to muck about decanting the wine.

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Supermarket Juice Wine Recipes and Wurzels Orange Wine (WOW) here - viewtopic.php?f=19&t=57
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Re: Acid

Postby oldbloke » Mon May 05, 2014 20:25

My kid took a tartaric crystal to school for show'n'tell once, after I mentioned they're called "wine diamonds".
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Re: Acid

Postby Gorty » Thu Oct 30, 2014 16:54

A question for the 'Great Masters of WOW' ....how do you accurately measure the acidity of your wine?

Buy wisely, brew carefully, drink copiously and stuff the rest!

Fermenting:

25L The Range 'MYO' Red.
25L The Range 'MYO' White.
5L 'WOW' Pineapple.
5L 'WOW' Blueberry.
5L 'WOW' Pomegranate.
5L 'WOW' Mango.

Clearing:

25L The Range 'MYO' White.
25L The Range 'MYO' Red.
5L 'WOW' Orange 2nd attempt.
5L 'WOW' Ribena.

Bottled:

5L 'WOW' First attempt.
5L 'WOW' Cranberry.
5L 'WOW' Apple.
5L 'WOW' Pomegranate.

Drinking:

25L The Range 'MYO' white.
25L The Range 'MYO' Red.
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Re: Acid

Postby Aleman » Thu Oct 30, 2014 20:41

Ritchies do a wine 'Acid measuring' kit. Basically you titrate the must with some 0.1M Sodium hydroxide and an indicator, that allows you to determine the acid content as parts per thousand as sulphuric. . . . It may seem crazy but it is much more meaningful and useful to winemakers than pH is.

please note:The use of punctuation, bold, underlining, italics, and different sized type, follows the convention used in writing, for many years, to place emphasis on the point being made, and to highlight the importance of that point in the opinion of the author. It is not the intention of the author to shout, if that was the case the author would adopt the, much more recent, convention of using all capital letters.
Albert Einstein wrote:Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.
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Re: Acid

Postby Gorty » Fri Oct 31, 2014 12:36

Thanks Aleman.

Buy wisely, brew carefully, drink copiously and stuff the rest!

Fermenting:

25L The Range 'MYO' Red.
25L The Range 'MYO' White.
5L 'WOW' Pineapple.
5L 'WOW' Blueberry.
5L 'WOW' Pomegranate.
5L 'WOW' Mango.

Clearing:

25L The Range 'MYO' White.
25L The Range 'MYO' Red.
5L 'WOW' Orange 2nd attempt.
5L 'WOW' Ribena.

Bottled:

5L 'WOW' First attempt.
5L 'WOW' Cranberry.
5L 'WOW' Apple.
5L 'WOW' Pomegranate.

Drinking:

25L The Range 'MYO' white.
25L The Range 'MYO' Red.
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Re: Acid

Postby Moley » Fri Oct 31, 2014 13:39

Gorty wrote:A question for the 'Great Masters of WOW' ....how do you accurately measure the acidity of your wine?


I have one of those pH testing pens - which I have never yet used. :whistle:

Actually, I have never noticed this guide to acids before and would be interested to find where Chippy copied it from, because he sure as hell didn't write it.



Edit: Found it :nono:
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